Carburetor



1,622,513 March 29, 1927 i s. B, HOLMES CARBURETOR Filed April '9, 1.923

O INVENTOR .STANLEY E l-/o/nfa ATTORNZ'GK Patented Mar. 29, 1927.

UNITED STATES STANLEY '.B. HOLMES, OF SEATTLE, WASHINGTON.

eamiunafr'on.

Application ltiled April 9, 1923. Serial No. 630,785'.

This invention` relates to improvements in earburetors, and has for itsprinclpal object to provide a carburetor into which gasoline may be fedfrom a supply tank at a lower level by means of sub-atmosphericpressure.

AAnother object of the invention resides in the provision of meanswhereby the connection with the sub-atmospheric pressure is .0automatically controlled to maintain the.

supply within the carburetor.

A further object is to provide a carburetor wherein there is anautomatic re ulation of air admitted tothe mixing cham er in pro- .5portion to the amount of gasoline consumed. Other objects reside in theprovision of means for effectively vaporizing and mixingdthe fuel beforeit passes into the manifol :o In accomplishing these 'and other objectsof the invention` I have provided the improved details of construction,the preferred forms of which are illustrated in theaccompanyingdrawings, wherein- Figure 1 is a side view of a carburetor constructedin accordance with the present invention. i

Figure 2 is an enlarged, sectional view of.

the same. Y.

Figure 3 is a detail, sectional 'view of the float actuated valvemechanism for controlling the vacuum pressure in the float chamber.

Referring more in detail to the several views of the drawings whereinlike reference numerals designate the same, or like parts.

1 designates, as a whole, a carburetor constructed in accordance withthe present invention, and comprising a vertical, tubular portion 2provided with a flange 3 at its upper end through which bolts, as at 4,are extended to securek the device to the fuel intake manifold of anengine. Cast integrally with the tube, at one side and near .5 its lowerend is a bowl forming a supply chamber 5, and fitted within the upperportion oit-this bowl is a cu which forms a float chamber 6 and over wich a cover plate 7 is fitted and secured to the bowl by screws 8 totightly close both against leakage. Extended forwardly from the base ofiloat `chamber and threaded into a boss 9 in base of bowl 5 is a' tube10 by which connection is made with a su ply tube 11 that may lead froma source o supply at a lower level than the carburetor. The tube has alaty eral extension 12 wherein is an upwardly directed opening 13` intothe bowl; this opening being normally covered by a valve plate 14mounted on guide pins 15 which will rise to permit a ow into the chamber5, but

'ill automatically lclose to prevent any backow. i

The flowv of gasoline from conduit 11 is automatically controlled by theaction of a float 16 located in chamber 6 and slidable on a valve pin 17extended centrally therethrough and downwardly through tube 10 ;l itbeing provided with a tapered lower end 18 adapted to a tapered valveseat 19. The

top of the fioat is engaged by the outer ends of weighted levers` 2Osupported pivotally, as at 21, from the cover 7 and having operativeconnection at their inner ends with the pin 17 in such manner thatlowering of the float will raise the pin to permit an inflow ofgasoline, and rising of the fioat will move the pin toward closedposition to cut oit the inflow.

Thetube 2 is open at its lower ends to provide an air intake passage 24directly into the manifold, and fitted within this passage in spacedrelation are rings 25 and 26 each tapered from its opposite sides to thecentral passage so as-to form Venturi, tubes, and beneath these arevalves 27 and 28 of the butterfly type operable respectively bymeansoutlets 37 lead into the Venturi opening' just above its mostrestricted part.

Likewise, in the ring 26 upper and lower annular passages 40 and 41 areformed from which outlets '42 and 43 lead .into the Venturi opening inalternating relation justabove the most restricted part of the passage.Passage 41 is connected by means of 'a passage 44 with thebottom ofsupply chamber 5, and passage 40 is fed by means of a passage-45 thatopens into the base of the well 35. To permit a read, rise and fall ofgasoline in chamber 5, an well 35, the former is provided through coverplate 7,

lli

fitted within the dome is a sleeve valve 52 that may be moved upwardlyto close the end of pipe 50, or downwardly to cover an opening 53 toatmosphere in the opposite side of the dome and offset from the openinginto pipe 50; the movement of the sleeve being limited by stops 54 and55. The sleeve is actuated by connection with the pin 17, the connectioncomprising a pair of'levers 56 pivotally connected attheirinner endswith a plate 57 mounted between adjusting nuts 58 on the pin and withtheir outer ends extended between flanges 59 on the interior of thesleeve. A tensioned spring 60 connects the arms so as to throw themquickly in opposite directions when actuated fromv one side to theother. Withthe parts as shown in Figure 3, the float chamber isconnected with the sub-atmospheric pressure in the manifold and gasolinemay be drawn into the chamber, but when the chamberis lled, the floatwill rise and cause pin l? to be moved downwardly. rThis will cause thepivoted inner ends of levers 56 to be moved past the dead center lineand spring 60 to snap them upwardly to throw the valve sleeve upwardlyto close pipe 50 and uncover the opening 53, thereby shutting od `thesub-atmospheric lpressure and allowing air to enterthe chamber throughport 53, so that the gasoline may flow out as needed through passage 13into chamber 5.

With the parts so constructed and assembled, operation would be as'follows:

On starting the engine to vwhich the carburetor is attached, valve 28would be closed while valve 27 is left open. Suction in the manifoldthen causes gasoline tov be drawn vinto the mixing passage 24 throughpassages ports 37 whereby it is finely vaporized and mixed withlair sothat a very small amount of gasoline 1s necessary. l

While driving the vehicle, valve 27 is ncaacia opened and the speedcontrolled by its adjustinent between opened and closed positions. ][twill be seen that gas will be taken in through passages dit and d5, andsince the hole 36 in bottom of well 35 is very small, the well will soonbe emptied and then air will be admitted through the well vand/passage45, and into the mixing tube suction manifold, a fioat chamber, a fuelstorage chamber adapted to be lled through y a back check valveconnection with the float chamber and having connection with a source ofyfuel supply, a valve in said fuel supply connection, a float forcontrolling `said valve, a cylindrical dome opening into the top of thefloat chamber and having an opening in the side thereof to outsideatmosphere, a suction conduit from the suction manifold opening into oneside of the dome in odset relation above the opening to at mosphere, asleeve slidably fitted in the dome and operable by the doat betweenpositions to cover either the opening to atmosphere or the opening tothe suction manifold.

2. lin a carburetor, in combination with a suction manifold, a Boatchamber, a Heat in the said chamber, a fuel storage chamber adapted tobe filled through a back check valve connection with the float chamberand having connection with a source of fuel supply, a valve stemadaptedto be actuated by the float to open or closed connection with saidsource of supply,y a cylindrical dome opening into the top of the floatchamber and having an opening in the side thereof to outside atmosphere,a suction conduit from the suction manifold opening into one side of thedome in oiiset relation above the` opening to atmosphere and a sleeveslidably fitted in the dome and movable to separately Icover either theopening to atmosphere or to the suction manifold, stops in the dome forlimiting the sleeve movement, yieldable trip members for shifting thesleeve from one position to another, and means connected with the valvepin for actuating the trip members.

Signed at Seattle, King County, Washington this 3rd day of April, 1923.

STANLEY B. HOLMES.

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